Inhibicion de Fusarium oxysporum por cepas mutantes de Pseudomonas fluorescens Zum80 incapaces de producir sideroforos | Fusarium oxysporum inhibition by Zum80 Pseudomonas fluorescens mutant strains unable to produce siderophores
2005
Valencia-Cantero, E. | Villegas-Moreno, J. | Sanchez-Yanez, J.M. | Pena-Cabriales, J.J. | Farias-Rodriguez, R.
Pseudomonas fluorescens strain ZUM80 is a siderophore-producing bacteria which inhibits the growth of phytopathogen microorganisms in limited iron conditions. To understand the mechanism of Fusarium oxysporum inhibition by the P. fluorescens ZUM80 strain, siderophore-negative mutant strains were obtained by exposition of P. fluorescens to nitrosoguanidine. Antibiosis assays in limited iron conditions showed that when F. oxysporum was inoculated with ZUM80 or derived mutant strains at least 48 h before, inhibition of the fungus was total. Nevertheless, when the fungus was inoculated 48 h before the bacteria, only the ZUM80 strain was able to inhibit the fungus. Under non-limited iron conditions, the ZUM80 strain did not inhibit F. oxysporum, but its siderophore-negative mutants did. The results suggest the existence of a diffusible metabolite different from siderophores, whose synthesis is regulated by iron and is capable of inhibiting the growth of F. oxysporum.
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